Effect of Increasing Concentration

Although the law has apparently been verified for solvents, in good solvents no single exponent can be supported, the answer being dependent upon the particular concentration range studied cf. ref. 72). 

The transition from dilute solution behaviour (isolated polymer coils) to semi-dilute (interpenetration of coils, uniform polymer segment density) usually occurs over a narrow range of concentration, and a critical concentration c identified. This c will, however, depend to some extent upon the particular experiment performed, e.g., solution viscosity, diffusion (cf., e.g., ref. 99)  

Kratochvil, in Light Scattering from Polymer Solutions, ed. M. Huglin, Academic Press, London New York, 1972, p. 333. 

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FIG. 18-28 Usually, the gas-liquid mass-transfer coefficient, K, is reduced with increased viscosity. This shows the effect of increased concentration of microbial cells in a fermentation process. 

Fig. 2. Effects of increasing concentrations of anti-igE on histamine secretion from eieven preparations of HHMC from patients undergoing heart transpiantation. Each point represents the mean SEM. 

Kempen et al. [176] synthesized a water-soluble cho-lesteryl-containing trigalactoside, Tris-Gal-Chol (I), which when incorporated in lipoproteins allows the utilization of active receptors for galactose-terminated macromolecules as a trigger for the uptake of lipoproteins. The effect of increasing concentrations of Tris-Gal-Chol on the removal of LDL and HDL from serum and their quantitative recovery in the liver is shown in Fig. 13. These data show that lipoproteins containing Tris-Gal-Chol can be used as a liver-specific drug-carrier system. 

On well characterised non-stabilized PP samples [48] having molar mass within 45-180 kg/mol with differing tacticity and crystallinity, we can see that the increasing molar mass leads to an increase of induction time and reduction of the maximum chemiluminescence intensity (Figure 14). The polymer with higher average molar mass appears to be more stable than that with lower molar mass. This may be ascribed to the effect of increased concentration of more reactive terminal groups, which promote initiation of thermal oxidation. 

Effect of increasing concentration of C-5 sulfonic acid on retention... 

As an example of the use of a Latin square as a fractional factorial design, suppose we want to find out the effect of increasing concentrations of a chemical added to retain gloss in an industrial paint formulation. The model is... 

With some simplification, theoretical models of adsorption lead to Equation 5.10 describing the effects of increasing concentration of the stronger (more polar) solvent, q), on decreasing retention factor, k in binary organic mobile phases [53] ... 

Figure 10.6 Effects of hydroxypropylation on the granule morphology of potato starches, (a) Potato starch granules after hydroxypropylation (at 10% propylene oxide concentration), (b) Effect of increased concentration of propylene oxide (15%) on the starch granule structure (source Kaur et al., 2004).

For example, suppose we examine the effects of increasing concentrations of de-naturant, which has two effects the intrinsic rate constants for folding, kf and kc, become lower, and the concentration of U increases relative to C. Initially, the change in concentration is not important while ATc-u is greater than 1, and so both mechanisms slow down because of the intrinsic rate constants decreasing. When [C] = [U] at higher concentrations of denaturant, kobs for scheme 18.13 slows down by a further factor of 2 since Kc /(1 + Kc v) — 0.5 (in equation... 

The most important effect of concentration polarization is to reduce the membrane flux, but it also affects the retention of macromolecules. Retention data obtained with dextran polysaccharides at various pressures are shown in Figure 6.12 [17]. Because these are stirred batch cell data, the effect of increased concentration polarization with increased applied pressure is particularly marked. A similar drop of retention with pressure is observed with flow-through cells, but the effect is less because concentration polarization is better controlled in such cells. With macromolecular solutions, the concentration of retained macromolecules at the membrane surface increases with increased pressure, so permeation of the macromolecules also increases, lowering rejection. The effect is particularly noticeable at low pressures, under which conditions increasing the applied pressure produces the largest increase in flux, and hence concentration polarization, at the membrane surface. At high pressure, the change in flux with... 

Figure 3. Effect of increasing concentrations of dopamine on basal (A) and (—fisoproterenol-induced (B) cyclic AMP levels in rat pars intermedia cells in culture. Cells were incubated for 30 min in DMEM containing 5 mM HEPES, 100 pM ascorbic acid, and the indicated concentrations of dopamine alone (A). In B, 30 nM (—(isoproterenol was present during the last 4 min of incubation. Data are expressed as percent of control (in the absence of dopamine). Control cyclic AMP levels were 0.96 0.10 and 5.29 0.13 pmol/2 X 10s cells in the absence (A) or presence (B) of 30 M (—(isoproterenol, respectively (41).

Figure 5. Effect of increasing concentrations of CRF on cyclic AMP content (A) and a-MSH release (B) in rat pars intermedia cells in culture. After 5 d in culture, cyclic AMP content and a-MSH release were measured after 10 min and 6 h of incubation, respectively, with the indicated concentrations of CRF. Dexamethasone (100 nM) was present for 24 h in the appropriate...

Figure 6. Effect of increasing concentrations of CRF on adenylate cyclase activity in bovine pars intermedia pituitary homogenate.

Fig. 11. Effect of increasing concentrations of EM-652, E2, ICI 182,780, droloxifene, ICI 164,384, and toremifene on [3H] l7(3-estradiol (E2) binding to the rat uterine estrogen receptor. The incubation was performed with 5 nM [3H] l7(3-estradiol for 2 hours at room temperature in the presence or absence of the indicated concentrations of unlabeled compounds (Martel et al., 1998a).

Since EM-800 is rapidly metabolized into the active compound EM-652 in intact cells, we compared the effect of increasing concentrations of the nonsteroidal antiestrogens EM-652 and EM-800 with those of hydroxytamoxifen and tamoxifen and of the steroidal antiestrogen ICI 164384 on basal and E2-induced cell proliferation in T-47D, ZR-75-1 and MCF-7 cells (Simard et al., 1997a). As illustrated in Fig. 20, a 10-day exposure to 0.1 nME2 increased the proliferation of T-47D cells 4.77-fold. This E induced stimulation of cell proliferation was competitively blocked by simultaneous incubation with EM-800, EM-652, hydroxytamoxifen, ICI 164,384, and tamoxifen at respective IC50 values of 0.148, 0.146, 0.522, 2.41, and about 100 nM. It can also be seen in Fig. 20 that none of these compounds affected basal T47-D cell proliferation when incubated alone. 

Fig. 20. Effect of increasing concentrations of EM-652, EM-800, ICI 164,384, 4 hydroxy-trans-tamoxifen (OH-TAM), or tamoxifen (TAM) on basal and E2-induced cell proliferation in T-47D human breast cancer cells. Three days after plating, cells were exposed for 10 days to the indicated concentrations of compounds in the presence or absence of 0.1 nMEg. Media were changed at 2- or 3-day intervals. At the end of the incubation period, cell number was determined by measurement of DNA content. Data are expressed as the means SEM of triplicate dishes. When the SEM overlaps with the symbol used, only the symbol is illustrated (Simard et at., 1997a).

Fig. 5. Lineweaver-Burk plot of the effect of increasing concentrations of template DNA on the incorporation of 3H-AMP into RNA by RNA polymerase of E. coli K-12, in the absence of...

We note that in this particular case, the reaction order at constant overpotential becomes independent of pH. When the pH is lowered, the effect of increasing concentration of the hydronium ion is exactly compensated by the influence of the variation of the reversible potential on the reaction rate. 

A different kind of enzyme. Figure 22.27 shows the response of acetyl CoA carboxylase to varying amounts of citrate. Explain this effect in light of the allosteric effects that citrate has on the enzyme. Predict the effects of increasing concentrations of palmitoyl CoA. 

Fig. 3. Effect of increasing concentrations of phosphate buffer, pH 7.0, on the adsorption of antibody-bound steroid. pH]Testosterone was incubated with antibody without added unlabeled testosterone. Hydroxyapatite suspensions in phosphate buffers of different molarities were added tubes were shaken and centrifuged, and the supernatants were counted. Phosphate buffer strengths recorded are the final concentrations after addition of the hydroxyapatite suspension.

Figure 4. Effect of increasing concentrations of AMP or ADP on the formation of CH. in the presence of ATP. Reaction mixture contained crude extract, 41,0 mg of protein methylcohalamin, 5.0 /xmoles ouabain,...

The proton nuclear magnetic resonance spectrum of lomefloxacin mesylate obtained in D2O at 25° C is given in Figure 5 (9). The spectrum was obtained on a Bruker AM-500 NMR Spectrometer operating at 500.13 MHz and was referenced to external TSP [3-(trimethylsilyl)propionic-2,2,3,3-d4 acid]. The chemical shifts and spectral assignments are provided in Table 2 (9,10). The effect of increasing concentrations of Al3+ on the... 

To account for the effect of increasing concentrations of an additive that is much less strongly adsorbed than the components, we rewrite the ternary competitive Langmuir isotherm by dividing numerator and denominator by 1 -I- bsCs (bs, second coefficient of the additive isotherm Cs additive concentration)... 

Figure 14 1, The effect of increasing concentrations of PBO un the pre-adult development of ft. Itibari (mean and confidence limits),...

The effects of increasing concentrations of 8-OHQ-5SA, OP, and aa D on the activity of carboxypeptidase at a constant substrate concentration of 0.02 M CGP are shown in Fig. 2. (Vallee and Neurath, 1955.) Activity of the inhibited reaction was expressed as per cent of the proteolytic coefficient observed at zero inhibitor concentration. The conditions of preincubation are indicated. Recent and unpublished data indicate the time course of the inhibitory effects of these agents OP in concentrations of 1 X 10" M causes 90 % inhibition of the reaction in 60 minutes. 80 % of the inhibition occurs in the first 15 minutes (Fig. 3), Addition of 1 X 10" M zinc ions to the enzyme thus inhibited restores enzymatic activity, demonstrating the reversibility of inhibition (unpublished results). Since inhibition did not occur when chelating agents were first incubated with zinc, cupric, or ferrous ions to form the respective metal chelate, it appeared that the sites of chelation of these compounds are responsible for the observed inhibition. Inhibition is therefore not caused by any structural similarity between the inhibitors and the substrate. 

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